Bottom-hole pressure testing apparatus



Dec. 20, 1960 D. w. REED BOTTOM-HOLE PRESSURE TESTING APPARATUS FiledSept 8, 195a FIG.

FIG.

FIG.

INVENTORI DAVIS W. REED BY: CMZZUI HIS AGENT United States PatentBOTTOM-HOLE PRESSURE TESTING APPARATUS Davis W. Reed, Ventura, Califi,assignor to Shell Oil Company, a corporation of Delaware Filed Sept. 8,1958, Ser. No. 759,589-

4 Claims. (Cl. 73-155) The present invention relates to well testingapparatus and pertains more particularly to apparatus adapted to bepositioned within an oil well for obtaining bottom hole pressuresthereof while the well is being pumped.

This invention finds particular utility in oil well pumping systemswherein downhole fluid-operated pumps of the reciprocating type areemployed for pumping oil and other fluids from the well. Influid-operated pumping systems of this character, an operating fluid,such as oil, is delivered to the fluid operated pump near the bottom ofthe well under pressure by way of a power-fluid supply line whichextends from a source of pressurized operating fluid at the surface ofthe group downwardly in the well to the pump. Such a fluid-operated pumpincludes a motor piston which is reciprocated in its cylinder by analternating fluid pressure differential applied thereto, and includes avalve for so regulating the delivery of the operating fluid to the motorcylinder and the exhaust of the spent operating fluid therefrom as toreverse the fluid pressure differential each time the motor, In such afluid piston reaches the end of its stroke. operated pump, the deliveryof the operating fluid to the motor cylinder from the power fluid supplyline is interrupted momentarily each time the motor piston reaches theends of its stroke with the result that the fluid pressure in thepower-fluid supply line increases momentarily, assuming that the rate ofdelivery of the operating fluid under pressure to the supply line issubstantially constant, which is usually the case.

In the conventional type of hydraulic pumping equipment, the fluidoperated pump is run into the production tubing within the well whilebeing secured to the lower end of the power-fluid supply line. If it isdesired to obtain pressures within the well, say at a level opposite theoil-producing Zone, it is necessary with the present equipment towithdraw the pump and inner power supply tubing string from the wellprior to lowering a pressure sensing and recording instrument down theproduction tubing while being attached to the well pump. With the pumpand power tubing string reinstalled in the well, the well is producedfor a predetermined time while borehole pressures are recorded by thepressure device adjacent to the pump, and thereafter the pump and powertubing string are again withdrawn from the well so that the pressurerecording instrument can be recovered from the well. The pressurerecording device is normally run into the well at the bottom of thepump.

It is, therefore, a primary object of the present invention to providean apparatus whereby bottom-hole operating pressures may be obtained ina well being pumped by a fluid-operated pump.

A further object of this invention is to provide apparatus whereby apressure-sensing and recording instrument may be positioned within thepower supply line to a fluid-operated pump in a manner such that thepressuresensing device is isolated from the pressure of the fluid supplyline while being exposed to. thewell pressures in;

2,964,942 Patented Dec. 20, 1960 the vicinity of an oil-producingformation while the pump is operating.

Another object of the present invention is to provide apparatus adaptedto be positioned in a well being pumped by means of a downholefluid-operated pump whereby a pressure-sensing instrument may be rundown to the bottom of the well, record bottomhole pressures for apredetermined time, and then readily withdrawn from the well withoutshutting the well down.

These and other objects of this invention will be understood from thefollowing description taken with reference to the drawing, wherein:

Figure l is a diagrammatic view, taken in partial longitudinalcross-section, of well testing apparatus of the present inventionillustrated in the position within the production tubing string of anoil well being produced by the fluid-operated pump.

Figure 2 is a diagrammatic view, taken in partial longitudinalcross-section, of another arrangement of the present well testingequipment, illustrated as being positioned in the production tubing of awell with a closure sleeve or plug substituted for a pressure-indicatingand recording device.

Figure 3 is a diagrammatic view, taken in partial longitudinalcross-section, of another arrangement of the present well testingequipment, shown as being positioned in a well tubing and having aninner power fluid tubing which is provided with an offset portion.

Referring to Figure 1 of the drawing, duction tubing string an oil wellprois illustrated as surrounding a power-fluid supply tubing string 11with a fluid-operated pump 12 of the reciprocating type being disposedin the lower end of the production tubing 11 and being operable by afluid under pressure in the supply tubing 11 to pump oil from a wellinto the production tubing 10 which conveys the oil upwardly to thesurface. The intake of the pump may be at 13 while fluid from the top isdischarged into the annular space 14 within the production tubing 10,when the pump is operating in an oil well which normally has aperforated casing (not shown).

The production tubing 10 extends upwardly to a well head assembly (notshown) at the top of the well while the power supply tubing extends tothe top of the well where it is connected to a source of operating fluidunder pressure, suchas a conventional pump (not shown) adapted todeliver the operating fluid under pressure at a substantially constantrate. Thus the power-fluid supply tubing 11 forms a supply line fordelivering the operating fluid under pressure to the fluid-operated pump12 in the well to operate it, the rate of delivery of the operatingfluid to the pump '12 being controlled by any suitable valve arrangement(not shown) at the surface. The pump 12 is positioned in a fluidtightmanner within the bottom of the production tubing 10, being removablysecured therein to permit it being readily withdrawn from the well.

Just above the pump 12, the power-fluid supply tubing 11 is providedwith the portion 15 having an enlarged cross-sectional area in whichportion 15 and instrument holder '16 may be fixedly positioned. Theinstrument holder 16 may take any form, but is preferably a tubularmember which is fixedly secured, as by welding, to the inner wall of thepower fluid tubing 11. One or more fluid ports 17 and 18 are provided inthe power tubing 11 and the production tubing 10, respectively, at apoint opposite the instrument holder 16 so that the interior of theinstrument holder 16 is in communication with the space outside theproduction tubing 10.

The instrument'holder '16 is provided with a suitable seat, preferablyat the top thereof, forseating an instrument 20 therein in afluidtightmanner. The instru.-.-,

ment 20 is diagrammatically illustrated as having a cylindrical housing"having a seat 21 near the upper end thereof, with a fishing head 22secured to the top thereof for withdrawing the instrument from theinstrument holder 16 in a manner well' known to theart. The instrument20 may be of any suitable designor construction of the type employed tomeasurepressures, temperatures, etc. at the bottom of a well. Since thedesign, construction or operating principle of the instrument 20 formsno part of this invention, the instrument will not be furtherdescribed'here.

border to prevent power fluid from draining from the supplytubing 11when an instrument is being lowered 'into'or withdrawn from the well, asuitable valve, "such as a spring-loaded sleeve valve 23 is slidablymounted within the instrument holder 16 to close port 17 when theinstrument 20 is withdrawn from the holder 16. A valve stop 24 may beprovided within the instrument holder 16 for limiting the upward travelof the springloaded sleeve valve 23. Additionally, a shoulder 25 may beformed on the outer surface of the instrument 20 for contacting the topof the sleeve valve 23 and opening it when the instrument 20 is droppedinto its holder 16. The shoulder 25 and the stop means 24 of suitabledimension or arrangement so that the shoulder 25 can pass through thestops 24.

Instead of employing a sleeve valve 23 to close port 17 when theinstrument 20 is withdrawn from service, the port 17 may be closed in amanner illustrated in Figure 2 wherein a dummy instrument or a closureplug 26 is dropped down the power supply tubing 11 andinto theinstrument holder 16 to top of the holder 16 in a fluidtight manner. Inthis arrangement the bottom 27 of the instrument holder 16 is normallyclosed.

The enlarged portion 15 of the tubing 11 may take any form of a by-passline around the instrument holder 16 and its instrument 20 so that thepower fluid can be readily pumped down through the supply tubing 11 andaround the instrument holder 16 to the pump 12 while the instrument ispositioned coaxially within the tubing 11. Alternatively, it is realizedthat the enlarged portion of a cross-sectional area may be formed bymeans of an ofiset portion 30 (Figure 3) in which the instrument 20 maybe positioned or withdrawn therefrom. In this arrangement a portion 37of the tubing wall .11 forms an instrument holder together with theoffset portion 30. In this case the ports 1'7 and 18 in the tubings 11-and 10, respectively, are positioned below theseat formed on 'the top ofthe tubing wall section 37.

A pair of packers 31 and 32 are provided within the production tubingabove and below the enlarged portion of the power-supply tubing therebyclosing the annular space between tubing string 10 and 11 in afluidtight rnanner. Positioned in the annular space 34- and extendingthrough the packers 31 and 32 is a'by-pass pipe 35 through whichproduction fluid from the pump 12 by-passes theportion of the :annulus34 between tubing strings-10 and 11, which is located between packers 31and 32, and is in communication throughports 17 and 18 with theinstrument and the pressure outside the tubing string 10. Thisproduction by-pass pipe 35 is of a size sufiicient to handle the flow offluid from the pump 12.

In operation, the present apparatus is employed to be used inconjunction with indicating and. recording devices to secure informationsuch as borehole pressures by dropping, or lowering on a wire line, aninstrument .20 through thepower supply tubing 11. so thatit seats in afluidtight manner within the instrument holder 16. :In the illustratedapparatus, the seating portion21 of the instrument 20 is of a diameterso that it passes readily through the power supply tubing 11. Theinstrument may be a self-contained type having aclock-typerrecorderbuilt .in itso that .a predeterminednumberof "pressure readingszmay-.bei:periodically :taken' within "the 'well with the instrument beinglater retrieved by a wire line. Alternatively the pressure recorder 20may be lowered on an electric cable extending upwardly through the powersupply tubing to the top of the well where it may be connected to asuitable recorder (not shown) or other equipment. Thus by using thepresent apparatus, pressure readings can be obtained at the bottom ofthe well being pumped with a fluid-operated pump of the reciprocatingtype while pumping operations are going on. In certain instances it isdesirable to obtain static bottomhole pressures when the pump is notoperating. At all times the pump is operating, the production fluidtherefrom together with the exhaust power oil used to operate the pumpis transmitted upwardly through the bypass pipe 35 and into the annulus34 to the surface of the well.

When the instrument 20 of Figure l is withdrawn from the instrumentholder 16, the spring-loaded sleeve valve 23 is forced upwardly to closeport 17. In the arrangement of Figure 3, when the instrument 20 waswithdrawn from its seat, a dummy instrument .or closure plug 26 (Figure2) would be lowered into the offset portion 31 to close port 17.

I claim as my invention:

1. Apparatus for obtaining bottom-hole pressures in an oil well beingpumped by a hydraulically-powered reciprocatingpurnping unit saidapparatus comprising a pro duction tubing string positioned in a casedoil well and extendingfrom the surface to an oil-producing leveltherein, a hydraulically-powered reciprocating pump positioned withinthe lower end of said production tubing, said pump having a dischargebeing in communication with said production tubing, a power-fluid tubingstring depending within said production tubing throughout the lengththereof, the lower end of said power-fluid tubing beingoperatively'connected to the upper end of said pump, said power-fluidtubing having a portion of enlarged crosssectional area located abovesaid pump, an instrument holder fixedly positioned within saidpower-fluid tubing in the enlarged portion thereof, said holder beingformed to provide a chamber for a pressure-measuring instrument, thewall of said power-fluid tubing being formed with first port means incommunication between the space outside the power-fluid tubing and theinterior of said instrument holder chamber, means normally closing saidfirst port'means when no instrument is within said instrument holder,the wall of said production tubing being formed with'second port meansat substantially the same level, closure means in the annulus formedbetween said produ tion tubing and said power-fluid tubing, said closuremeans being positioned above and below said first and second ort means,and conduit means extending through said closure means in opencommunication between the annulus above the upper closure means and theannulus below the lower closure means.

2. Apparatus for obtaining bottom-hole pressures in an oilwell beingpumped by a hydraulically-powered reciprocating pumping unit saidapparatus comprising a production tubing string positioned in a casedoil well and extending from the surface to an oil-producing leveltherein, a hydraulically-powered reciprocating pump positioned withinthe lower end of said production tubing, said pump having a dischargebeing in communication with said production tubing, a power-fluid tubingstring depending within said production tubing throughout the lengththereof, the lower end of said power-fluid tubing being operativelyconnected to the upper end of said pump, said power-fluid tubing havinga portion of enlarged crosssectional area located above said pump, aninstrument holder fixedly positioned on the inner wall of saidpowerfiuid tubing in the enlarged portion thereof, said holder beingformed to provide a chamber for a pressure-measuring instrument, a seatformed on said instrument holderffor seating an instrument therein inafluidtight manner, the walltoti said instrument holder below the. seat.thereot and the wall of said power-fluid tubing being formed withcommon first port means in communication with the space outside thepower-fluid tubing, means normally closing said first port means when noinstrument is Within said instrument holder, the wall of said productiontubing being formed with second port means at substantially the samelevel, closure means in the annulus formed between said productiontubing and said power-fluid tubing, said closure means being positionedabove and below first and second port means, and conduit means extendingthrough said closure means in open communication between the annulusabove the upper closure means and the annulus below the lower closuremeans.

3. Apparatus for obtaining bottom-hole pressures in an oil well beingpumped by a hydraulically-powered reciprocating pumping unit saidapparatus comprising a production tubing string positioned in a casedoil well and extending from the surface to an oil-producing leveltherein, a hydraulically-powered reciprocating pump positioned withinthe lower end of said production tubing, said pump discharge being incommunication with said production tubing, a power-fluid tubing stringdepending within said production tubing throughout the length thereof,the lower end of said power-fluid tubing being operatively connected tothe upper end of said pump, an instrument holder fixedly positioned onthe inner wall of said power-fluid tubing near the lower end in a mannerso as to form, conduit means around said instrument holder incommunication with the power-fluid tubing above and below saidinstrument holder, said holder being formed to provide a chamber for apressure-measuring instrument, the wall of said power-fluid tubing beingformed with first port means therethrough in communication between thespace outside the power-fluid tubing and the interior of said instrumentholder chamber, means normally closing said first port means when noinstrument is within said instrument holder, the wall of said productiontubing being formed with second port means at substantially the samelevel, closure means in the annulus formed between said productiontubing and said power-fluid tubing, said closure means being positionedabove and below said first and second port means, and conduit meansextending through said closure means in open communication between theannulus above the upper closure means and the annulus below the lowerclosure means.

4. Apparatus for obtaining bottom-hole pressures in an oil well beingpumped by a hydraulically-powered recipro cating pumping unit saidapparatus comprising a production tubing string positioned in a casedoil well and extending from the surface to an oil-producing leveltherein, a hydraulicallypowered reciprocating pump positioned within thelower end of said production tubing, said pump discharge being incommunication with said pro duction tubing, a power-fluid tubing stringdepending within said production tubing throughout the length thereof,the lower end of said power-fluid tubing being operatively connected tothe upper end of said pump, said power-fluid tubing having an axiallyoffset portion forming an instrument holder within said power-fluidtubing, said holder being formed to provide a chamber for apressure-measuring instrument, an instrument adapted to be seatedtherein in a fiuidtight manner, the wall of said power-fluid tubingbeing formed with first port means through the wall thereof incommunication with the space outside thereof, means normally closingsaid first port means when no instrument is within said instrumentholder, the wall of said production tubing being formed with second portmeans at substantially the same level, closure means in the annulusformed between said production tubing and said power-fluid tubing, saidclosure means being positioned above and below said first and secondport means, and conduit means extending through said closure means inopen communication between the annulus above the upper closure means andthe annulus below the lower closure means.

References Cited in the file of this patent UNITED STATES PATENTS2,703,585 Coberly Mar. 8, 1955 2,846,014 Dafiin et al. Aug. 5, 19582,846,876 Willingham Aug. 12, 1958 2,856,008 Spencer Oct. 14, 1959

